var big = document.querySelectorAll('.mbottom .mbtab span')
var midd = document.querySelectorAll('.mbottom .mbdiv div')
var sms = document.querySelectorAll('.mbottom .mbddiv div')
var mia = document.querySelectorAll('.mbottom .mbdiv div a')
for (let i = 0; i < big.length; i++) {
    big[i].index = i
    big[i].onmouseover = function () {
        for (var j = 0; j < big.length; j++) {
            midd[j].index = j
            midd[j].onmouseover = function () {
                midd[this.index].className        
                mia[this.index].className = 'active'
            }
            sms[j].className = ''
            midd[j].className = ''
            big[j].className = ''
            this.className = 'active'
            midd[this.index].className = 'dctive'
            sms[this.index].className ='dctive'
        }
    }
}